What Is Meningitis?

Meningitis is an inflammation of the meninges. This is the membrane that covers the brain and spinal cord. Meningitis may occur when fluid surrounding the meninges becomes infected.

The most common causes of meningitis are viral and bacterial infections. Meningitis is contagious. It can be transmitted by coughing, sneezing, or close contact. Other causes include:

cancer

chemical irritation

fungi

drug allergies

Bacterial meningitis is a medical emergency. It can be fatal.

Types of Meningitis

The most common causes of meningitis are viruses and bacteria.

Aseptic (Viral) Meningitis

Viral meningitis usually occurs in children under the age of five. It is most common during the early fall. Thirty percent of cases are caused by enteroviruses. These viruses normally cause intestinal illnesses. West Nile virus, and influenza can also cause meningitis.

Viral meningitis is more common in adults under the age of 30 than in older adults. Outcomes are usually better than bacterial meningitis. It can resolve on its own.

Bacterial Meningitis

Bacterial meningitis is contagious. It can also be life-threatening. Up to 40 percent of children and half of adults with this condition die. This is true even with proper treatment. The types of bacterial meningitis are:

meningococcal

pneumococcal

staphylococcal

tuberculous

gram negative

There are several other types of meningitis. Cryptococcal is caused by a type of yeast. Carcinomatous is cancer-related.

Symptoms of Meningitis

Symptoms of meningitis vary by age.

Teens and young adults may have:

headaches

fever

stiff neck

drowsiness

seizures

Infants may:

be irritable

refuse to eat

cry when being held

have bulging fontanelles (soft spots on the top of the head)

Young childrenmay:

cough

have trouble breathing

Older adults may have:

a slight headache

fever

Meningitis can also cause a change in mental status and sensitivity to light.

Seek immediate medical attention if you experience these symptoms. Bacterial meningitis can be deadly. There is no way to know if you have bacterial or viral meningitis by how you feel.

Risk Factors for Meningitis

There are several risk factors for meningitis.

Compromised Immunity

People with immune deficiency are more vulnerable to infections. This includes those that cause meningitis. People with HIV/AIDS can get pneumocystic meningitis. It is unusual in the general population.

Community Living

Meningitis is easily spread when people live in close quarters. Small spaces increase the chance of exposure. Some high risk locations include:

college dormitories

barracks

boarding schools

day care centers

Pregnancy

Pregnant women have an increased risk of listeriosis. This form of meningitis is caused by listeria bacteria. Infection can spread to the unborn child.

Age

The average age for bacterial meningitis is 25 years. Viral meningitis is most frequently seen in children under the age of five.

Working with Animals

Farm workers and others who work with animals have increased risk of infection with listeria.

Diagnosing Meningitis

Diagnosing meningitis starts with a health history and physical exam. Age, dorm residence, and day care center attendance can serve as important clues. A physical exam may show:

fever

increased heart rate

neck stiffness

reduced consciousness

Meningitis is usually diagnosed with a lumbar puncture. This test is also called a spinal tap. It allows doctors to look for increased pressure in the central nervous system. It can also find inflammation or bacteria in the spinal fluid. This test can also help determine the best antibiotic for treatment.

Other tests may also be ordered to diagnose meningitis.

CBC with Differential is a general index of health. It checks the number of red and white blood cells. White blood cells fight infection. The count is usually elevated in meningitis.

Blood cultures look for bacteria in the blood. Bacteria can travel from the blood to the brain. Meningococcus and pneumococcus can cause both sepsis and meningitis.

Chest x-rays can reveal the presence of pneumonia, TB, or fungal infections. Meningitis can occur after pneumonia.

A CT scan of the head can show problems like brain abscess or sinusitis. Bacteria can spread from the sinuses to the meninges.

Treating Meningitis

Treatment is determined by the cause of meningitis.

Bacterial meningitis requires immediate hospitalization. Treatment will be with intravenous antibiotics. Early diagnosis and treatment are important. They help prevent brain damage and death. There is no specific antibiotic for meningitis. It depends on the bacteria involved.

Fungal meningitis is treated with anti-fungal agents.

Viral meningitis isn’t treated. It usually resolves on its own. Symptoms should go away within two weeks. There are no serious long-term problems associated with viral meningitis.

Complications from Meningitis

The following complications are associated with meningitis:

seizures

hearing loss

brain damage

hydrocephalus (water on the brain)

subdural effusion (buildup of fluid between the brain and the skull)

Preventing Meningitis

Preventive antibiotics are given to close contacts of people with meningococcal infection.

Vaccinations can also protect against certain types of meningitis. Vaccines that can prevent meningitis include:

HiB vaccine (Haemophilus vaccine)

Pneumococcal conjugate vaccine

Meningococcal vaccine

Who Should Be Vaccinated Against Meningococcal Meningitis?

The following groups should get a meningitis vaccine:

college freshmen who live in dorms and haven’t been vaccinated

adolescents aged 11 to 12

new high school students who haven’t been vaccinated

those traveling to countries where meningococcal disease is common

children age two or older who don’t have a spleen or are immunocompromised